> 3. Do we really require NCHAr and NVARCHAR2 datatypes, will
> CHAR/VARCHAR2 won't suffice?
> 4. If we do have to select NCHAR/NVARCHAR2 then what is the
> sequence of doing/setting this, since i was trying to
> assign a string to NCHAR, an error of character set was
> given by the system.

Most likely, what you are trying to do doesn't require NCHAR/NVARCHAR2
in Oracle8/Oracle8i.

> 5. If we chose UTF-8, then do we have to change the column
> width to say 40 (for a double byte character set e.g.,
> Korean) if it was earlier defined to be at 20(while using
> a Single Byte character set e.g. English).

Since Korean characters cannot be represented in single-byte character
set, it's not correct to say "Korean takes double space as English".
The correct way is, if the original contents are English, we need to
come up with the number of Korean characters to express the same meaning
as English, then multiply it by 3 if you are using UTF-8 (because one
Korean Hangul character takes 3 bytes in UTF-8). If 10 Korean Hangul
characters can express the same meaning as 20 English characters, you
need 30 bytes for this column. Please note that the situation really
varies. For example, if you are storing people's full names, they are
often longer in Spanish than English. The difference between English
and Spanish could possibly be bigger than the difference between English
and Korean.